1. Field of the Invention
The present invention relates to image processing, more particularly, to a verification method for determining areas within an image corresponding to monetary banknotes.
2. Description of the Prior Art
Improvements in graphics and image duplication systems, which can include scanners, digital color copiers, and printing machinery and apparatuses, has also contributed to the increase in illegal counterfeit reproduction of various items. Counterfeiters nowadays commonly attempt the reproduction of monetary banknotes, currencies, stocks, bonds, and other valuable items for personal gain and profit. The task of distinguishing and discerning between legitimate items and copied fakes becomes increasingly difficult as printing and reproduction improvements allow copiers to reproduce banknotes that are virtually identical to legitimate ones. Therefore, there is a need to be able to effectively and precisely discern and distinguish counterfeited banknotes from authentic ones.
Banknote detection systems today typically incorporate a scanner or scanning mechanism of sorts. This converts information from a sample banknote into a digital data format representation for image processing. Once converted into digital data, a series of tests and procedures can be performed in order to confirm the validity of the sample banknote. This may include the identification of key features, such as landmarks, holograms, colors, serial numbers and pigments.
An important aspect of counterfeit currency detection prior to identification of key features involves the verification of areas corresponding to the monetary banknote within the scanned image. Often times, the size of the image is greater than that of the banknote. The valid location of banknotes within the image is thus required so that relevant counterfeiting tests can be performed on the confirmed areas, and not on the background image. Additionally, knowing the areas corresponding to the banknote will allow determination of a coordinate system for referencing in further tests.
If the banknote is scanned while imposed on a complicated background, the difficulty associated with distinguishing the actual banknote location increases. Background noise and patterns may further complicate the detection process. This may introduce irregularities, and invalid background objects can be misinterpreted as a banknote location. Variations in the shift, rotation and alignment of banknotes within the image may also complicate identification processes as a set frame of reference cannot be initially implemented.
Without the proper verification of banknote locations within a scanned image, being separated from the background image, optimal conditions for accurate counterfeit currency detection cannot be met.